@inbook {900, title = {Schalenf{\"o}rmige Hybridverbunde und Inserts}, booktitle = {Intrinsische Hybridverbunde f{\"u}r Leichtbautragstrukturen}, volume = {1}, year = {2021}, pages = {11-120}, publisher = {Springer Vieweg}, organization = {Springer Vieweg}, chapter = {2}, address = {Berlin, Heidelberg}, abstract = {Schalenf{\"o}rmige Bauteile zeichnen sich durch ein sehr gro{\ss}es Verh{\"a}ltnis von Breite oder L{\"a}nge zur Wanddicke aus. Durch die geringe Wandst{\"a}rke kommt der Einleitung von Lasten in derartige Strukturen eine besondere Bedeutung zu. Hierf{\"u}r werden h{\"a}ufig spezielle Lasteinleitungselemente (Inserts) in die Struktur eingebracht, die als Anbindungspunkte dienen. Die Kombination von metallischem Lasteinleitungselement und CFK-Struktur wird anhand drei verschiedener Teilprojekte untersucht. Im Projekt {\quotedblbase}Multilayer-Inserts {\textendash} Intrinsische Hybridverbunde zur Krafteinleitung in d{\"u}nnwandige Hochleistungs-CFK-Strukturen{\textquotedblleft} wurde ein Lasteinleitungselement f{\"u}r automatisiert gefertigte Faserverbundstrukturen entwickelt. Das Projekt {\quotedblbase}Grundlagenuntersuchungen intrinsisch gefertigter FVK/Metall-Verbunde {\textendash} vom eingebetteten Insert zur lasttragenden Hybridstruktur{\textquotedblleft} untersucht die faserschonende, intrinsische Herstellung von FVK/Metall-Verbunden im RTM-Prozess anhand verschiedener Hybridisierungsans{\"a}tze. Im Projekt {\quotedblbase}Einfluss, Detektion und Vorhersage von Defekten in gro{\ss}serientauglichen Hybridverbunden f{\"u}r Metall/CFK-Leichtbautragstrukturen{\textquotedblleft} wurde ein neuartiges Anbindungskonzept f{\"u}r Metall-CFK-Hybridstrukturen mit thermoplastischer Zwischenkomponente entwickelt. Im Rahmen dieses Kapitels werden die Ergebnisse der Teilprojekte detailliert vorgestellt und er{\"o}rtert.}, isbn = {978-3-662-62832-4}, issn = {978-3-662-62833-1}, doi = {https://doi.org/10.1007/978-3-662-62833-1_2}, url = {https://link.springer.com/chapter/10.1007\%2F978-3-662-62833-1_2}, author = {Henning, Frank and Bernath, Alexander and Bretz, Lucas and Denkena, Berend and Fleischer, J{\"u}rgen and Gro{\ss}, Lukas and Fabian G{\"u}nther and H{\"a}fner, Benjamin and Herrmann, Hans-Georg and Herwig, Alexander and Horst, Peter and Jost, Hendrik and Vanessa Kretzschmar and Lanza, Gisela and Meiners, Dieter and Muth, Markus and Markus Pohl and Roth, Sven and Schmidt, Carsten and Schwarz, Michael and Gonzalez, Jonathan Serna and Seuffert, Julian and Markus Stommel and Summa, Jannik and Weidenmann, Kay and Weykenat, Jannik} } @proceedings {867, title = {Design and quality assurance of intrinsic hybrid metal-CFRP lightweight structures}, year = {2020}, publisher = {DGM - Deutsche Gesellschaft f{\"u}r Materialkunde e.V}, address = {Web-Conference, Germany}, abstract = {The intrinsic production of metal-CFRP (carbon fiber reinforced polymers) hybrid structures allows a load-path-optimal design of connecting components. The interface of the hybrid part is of particular importance in design, production, and testing due to its force-transferring function. The special feature of the intrinsic connection is a thermoplastic jacket around the metal insert. It dampens vibrations, inhibits corrosions, and smoothens the stiffness gradient at the interface of metal and CFRP. A punched metal insert guarantees the suitability for mass production in the automotive industry, while the plastic jacket maintains a fiber adjusted geometry as well as a structured surface to maximize the joint strength. Load paths, stress distribution, and good drapability are taken into account. Finite element (FE) simulations and experiments are used to design and dimension the insert. Novel FE visualization methods for constructive design are developed and applied. The investigation of design elements on the mesoscale (mm) and microscale ({\textmu}m) surface roughness shows improvements of the load transfer and reduces the damage propagation. The intrinsic manufacturing is carried out by means of the resin transfer molding (RTM) process. Inline quality assurance starts with the inspection of the preform geometry. The data from two laser light section sensors are used for in-line measurements of complex 3D geometries. Ultrasonic sensors are used to check the curing degree of the resin during the infiltration. Afterwards, in-line quality assurance of the finished hybrid component is carried out by data fusion of laser light section sensors and active thermography. The data fusion enables a three-dimensional representation of the thermographic image and, thus, also a three-dimensional defect localization. Active and passive thermography are suitable for characterizing the component under various load conditions. Damages can be reliably detected using active thermography, while passive thermography allows the in-situ observation of the damage propagation. This allows a detailed insight into the damage mechanisms under quasi-static and cyclic load. It is possible to predict the remaining service life of the component by observing the delamination growth under cyclic mechanical load. The input of the in-line quality information in combination with the damage characteristics into a FE simulation enables the prediction of the individual component performance.}, url = {https://hybrid2020.dgm.de/fileadmin/Tagungen/2020/2020-04-Hybrid-Materials/02-Graphik-Druckwerke/2020-Hybrid-Proceedings.pdf}, author = {Lucas Bretz and Fabian G{\"u}nther and Hendrik Jost and Michael Schwarz and Vanessa Kretzschmar and Markus Pohl and Lukas Weiser and Benjamin H{\"a}fner and Jannik Summa and Hans-Georg Herrmann and Markus Stommel and Gisela Lanza} } @conference {868, title = {Tensor Spines - A Hyperstreamlines Variant Suitable for Indefinite Symmetric Second-Order Tensors}, booktitle = {IEEE Pacific Visualization Symposium (PacificVis)}, year = {2020}, month = {05/2020}, publisher = {IEEE}, organization = {IEEE}, address = {Tianjin, China}, abstract = {Modern engineering uses optimization to design long-living and robust components. One part of this process is to find the optimal stress-aware design under given geometric constraints and loading conditions. Tensor visualization provides techniques to show and evaluate the stress distribution based on finite element method simulations. One such technique are hyperstreamlines. They allow us to explore the stress along a line following one principal stress direction while showing the other principal stress directions and their values. In this paper, we show shortcomings of this approach from an engineer{\textquoteright}s point of view and propose a variant called tensor spines. It provides an improved perception of the relation between the principal stresses helping engineers to optimize their designs further.}, isbn = {978-1-7281-5697-2}, doi = {https://doi.org/10.1109/PacificVis48177.2020.1008}, url = {https://ieeexplore.ieee.org/abstract/document/9086282}, author = {Vanessa Kretzschmar and Fabian G{\"u}nther and Markus Stommel and Gerik Scheuermann} } @proceedings {880, title = {Visualization Framework for Assisting Interface Optimization of Hybrid Component Design}, volume = {25}, year = {2020}, month = {09/2020}, address = {T{\"u}bingen, Germany}, abstract = {Reliable component design is one of structural mechanics{\textquoteright} main objectives. Especially for lightweight constructions, hybrid parts made of a multi-material combination are used. The design process for these parts often becomes very challenging. The critical section of such hybrid parts is usually the interface layer that often builds the weakest zone. In this paper, we study a hybrid part made of metal and carbon fiber-reinforced composite, where the metal insert is coated by a thermoplastic to decrease the jump in stiffness between the two primary structural materials. To prevent stress peaks in small volumes of the part , mechanical engineers aim to design functional elements at the thermoplastic interface, to homogenize the stress distribution. The placement of such load transmitting functional elements at the thermoplastics interface has a crucial impact on the overall stability and mechanical performance of the design. Resulting from this, mechanical engineers acquire large amounts of simulations outputting multi-field datasets, to examine the impact of differently designed load transmitting elements, their number, and positioning in the interface between metal and composite. In order to assist mechanical engineers in deeper exploration of the often numerous set of simulations, a framework based on visual analytics techniques was developed in close collaboration with engineers. To match their needs, a requirement analysis was performed, and visualizations were discussed steadily. We show how the presented framework helps engineers gaining novel insights to optimize the hybrid component based on the selected load transmitting elements.}, doi = {https://doi.org/10.2312/vmv.20201188}, url = {https://diglib.eg.org/handle/10.2312/vmv20201188}, author = {Vanessa Kretzschmar and Christina Gillmann and Fabian G{\"u}nther and Markus Stommel and Gerik Scheuermann} } @conference {848, title = {Interlocking Interface Design in Metal-CFRP Joints using a Monte-Carlo Simulation Approach}, booktitle = {22nd International Conference on Composite Materials (ICCM)}, year = {2019}, address = {Melbourne (AUS)}, abstract = {Experimental single lap joint tests with different interlocking structures in the interface area of carbon fiber reinforced plastic and thermoplastic parts motivates an extended simulative study about the influences of interlocking elements. Due to a lack of information from a small number of experimental test with interlocking elements, conclusions are hard to draw about how to place structures elements in multi material joint interface. A Monte-Carlo simulation approach with a large number of simulations is used to provide more general explanations of the effects and interaction within interlocking interface boundaries. The derived conclusions are a wide distribution of pins, a certain pin density, as well as a staggered positioning of pins to achieve a maximum load capacity and minimum damage initiation in the composite for small displacements.}, author = {Fabian G{\"u}nther and Vanessa Kretzschmar and Gerik Scheuermann and Markus Stommel} } @proceedings {803, title = {Optimising Mechanical Interlocking Interface of CFRP-(thermoplastic/metal)-hybrids}, volume = {3}, year = {2018}, pages = {254-260}, publisher = {Deutsche Gesellschaft f{\"u}r Materialkunde e.V. (DGM)}, address = {Bremen, Germany}, abstract = {This contribution is about the experimental and numerical investigation of cfrp thermoplast interface joint strength. In tensile tests the joint strength of lap-shear-joints with cfrp thermoplast hybrid specimens with different surface structures are investigated. Comparing to a smooth reference, pin structures show the highest increase in joint strength up to 500 \%. In FE simulation the optimal geometry for pins is determined to an ellipse. Further, the strengthening effect of pins towards the displacement reduction in joint interface is shown. Here, elliptic pins which are stretched in load direction are found to be most feasible in this application. Finally, three different visualisation techniques are introduced to determine pin{\textquoteright}s position on interface surfaces.}, issn = {978-3-88355-417-4}, url = {https://hybrid2018.dgm.de/fileadmin/Tagungen/2018/2018-04_Hybrid_Materials/02_Druckwerke/2018-Hybrid-Proceedings.pdf}, author = {Fabian G{\"u}nther and Markus Pohl and Markus Stommel and Vanessa Kretzschmar and Gerik Scheuermann} } @article {786, title = {Tensor Field Visualization using Fiber Surfaces of Invariant Space}, journal = {IEEE Transactions on Visualization and Computer Graphics}, volume = {25}, year = {2018}, month = {01/2019}, pages = {1122-1131}, chapter = {1122}, abstract = {Scientific visualization developed successful methods for scalar and vector fields. For tensor fields, however, effective, interactive visualizations are still missing despite progress over the last decades. We present a general approach for the generation of separating surfaces in symmetric, second-order, three-dimensional tensor fields. These surfaces are defined as fiber surfaces of the invariant space, i.e. as pre-images of surfaces in the range of a complete set of invariants. This approach leads to a generalization of the fiber surface algorithm by Klacansky et al. [16] to three dimensions in the range. This is due to the fact that the invariant space is three-dimensional for symmetric second-order tensors over a spatial domain. We present an algorithm for surface construction for simplicial grids in the domain and simplicial surfaces in the invariant space. We demonstrate our approach by applying it to stress fields from component design in mechanical engineering.}, keywords = {fiber surface, Geometry, interaction, invariants, Mechanical engineering, Neuroscience, Strain, Tensile stress, tensor field, Visualization}, issn = {1077-2626}, doi = {10.1109/TVCG.2018.2864846}, url = {https://ieeexplore.ieee.org/document/8447439}, author = {Felix Raith and Christian Blecha and Thomas Nagel and Francesco Parisio and Olaf Kolditz and Fabian G{\"u}nther and Markus Stommel and Gerik Scheuermann} } @conference {671, title = {Feature-Based Tensor Field Visualization for Fiber Reinforced Polymers}, booktitle = {IEEE Conference on Scientific Visualization (SciVis)}, year = {2015}, publisher = {IEEE}, organization = {IEEE}, address = {Chicago}, author = {Valentin Zobel and Markus Stommel and Gerik Scheuermann} } @article {611, title = {Optimization strategy for the design of ribbed plastic components}, journal = {Journal of Plastics Technology}, year = {2014}, author = {Marc Sch{\"o}neich and Markus Stommel and Andrea Kratz and Valentin Zobel and Gerik Scheuermann and Ingrid Hotz and Bernhard Burgeth} } @conference {590, title = {Tensor Visualization Driven Mechanical Component Design}, booktitle = {In Proc. PacificVis, 2014, IEEE}, year = {2014}, publisher = {IEEE}, organization = {IEEE}, author = {Andrea Kratz and Marc Schoeneich and Valentin Zobel and Ingrid Hotz and Bernhard Burgeth and Gerik Scheuermann and Markus Stommel} }